1. Field of the Invention
The present invention relates to a moving mechanism for a blast gun for a blasting machine, and more particularly relates to a moving mechanism for a blast gun which is disposed inside and outside a blasting chamber and which moves the blast gun in a desired movement trajectory pattern, the blast gun having a nozzle which ejects a mixed fluid, composed of a compressed gas and an abrasive, on a surface of a workpiece (hereinafter, the surface and the workpiece are collectively called “workpiece surface”) which is to be subjected to machining or processing (hereinafter simply referred to as “processing”). In addition, some models have a blast gun provided with a trigger which is operated to eject and stop the mixed fluid or a foot pedal which is operated instead of the trigger.
2. Description of the Related Art
Blasting machines ejecting an abrasive together with compressed air are used for applications such as polishing or cutting of various goods, deburring for electronic components, and surface cleaning; in addition, blasting machines may also be used for various applications in a range of fields. For example, when spherical shots are used as an abrasive to be ejected, a blasting machine may be used for shot peening treatment.
In this specification, the “abrasive” includes one type of various powders, particles, fluid, and the like, which are ejected by a blasting machine, or a mixture thereof, the powders and the particles having desired particle diameter, shape, material, hardness, and elasticity. In addition, in order to perform desired processing, besides abrasive grains used, for example, for cutting, grinding, and polishing of workpiece surfaces, the abrasive includes resin particles or pulverized seed shells, used for surface cleaning or the like, and metal spheres used for the shot peening described above as well as blasting, a material having a grid shape or ceramic spheres are also included. In addition, the blasting machine of the present invention includes various suction-type and direct-pressure type machines which can be used for the various applications described above.
In order to prevent a degradation in the working environment caused by the abrasive, a crushed powder thereof generated by ejecting, and dust such as a cut powder generated from workpiece surfaces, the blasting machine described above is configured such that the workpiece and the blast gun are accommodated in a blasting chamber formed inside a cabinet and the abrasive is ejected in this blasting chamber.
In addition, various proposals have been made in order to move the blast gun accommodated in the blasting chamber in accordance with the shape of a workpiece surface or a portion to be processed, and/or in order to perform various operations, such as an operation for changing an ejecting direction.
The simplest structure for operating the blast gun described above has an opening for operation formed in a front or a side surface of the cabinet defining the blasting chamber so that an operator can insert his or her hand through this opening. In this structure, the blast gun is held by the hand inserted into the blasting chamber through the opening for operation and is moved and operated manually in accordance with the shape of the workpiece surface, the portion to be processed, or the like so as to perform desired processing.
In addition, a blasting machine having a driving device or the like which moves a blast gun disposed in a blasting chamber has also been proposed. As one example, a machine has been proposed in which, in order to enable a blast gun provided with a pipe extending to the outside of a blasting chamber to move in the blasting chamber, a slit is formed in a top plate of a cabinet through which the pipe is inserted, and a moving mechanism moving this blast gun in a longitudinal direction of the slit is provided outside the blasting chamber (Japanese Unexamined Patent Application Publication No. 2002-52471).
Furthermore, besides the blasting machines described above, a blasting machine having a structure in which an entire driving mechanism for a blast gun is disposed in a blasting chamber has also been proposed. An example of this type of blasting machine is one in which a robot for operating a blast gun is disposed in a blasting chamber.
Among the related arts described above, in the method in which an operator's hand is inserted into the blasting chamber through the opening for operation, in order to prevent the dust generated in the blasting chamber from leaking outside through the opening for operation, when the opening for operation is sealed off, for example, by a rubber glove into which the operator's fingers are inserted, and the operator holds the blast gun through the glove sealing off this opening for operation, the airtightness of the blasting chamber is maintained, and hence the dust is prevented from leaking outside the machine.
In the method described above, although the dust is prevented from leaking outside the blasting chamber, the blast gun disposed in the blasting chamber is operated only manually, and hence this type of machine is not suitable for performing operations for mass processing or the like, in which the blast gun is repeatedly and continuously made to perform a fixed movement.
On the other hand, according to the structure in which the driving device is provided in the blasting chamber, when the blast gun is moved by the driving device in accordance with a predetermined motion, the same operation can be repeatedly and continuously performed; therefore, this type of blasting machine is suitable, for example, for mass processing of identical products.
However, according to the blasting machine having the above structure, the slit formed in the cabinet must be larger than the pipe diameter in order to ensure a movable region of the blast gun in the blasting chamber, and hence anti-dust measures must be taken in order to prevent the dust from leaking outside the machine through this part.
As the anti-dust measures, in the blasting machine disclosed in Japanese Unexamined Patent Application Publication No. 2002-52471, short rubber split curtains are hung at the above slit portion, through which the pipe communicating with the blast gun is inserted, so as to surround the pipe, thereby preventing the dust from leaking through the slit portion (FIGS. 2 and 3 of Japanese Unexamined Patent Application Publication No. 2002-52471).
As described above, when it is intended to move the blast gun, which is disposed inside the blasting chamber from outside thereof, a slit or the like must be formed in the cabinet, and in addition, in order to prevent the dust leaking from this slit, anti-dust measures must be taken. As a result, the number of parts forming the blasting machine is inevitably increased.
Furthermore, even when the anti-dust measures as described above are taken, the slit cannot be completely sealed off, and hence it is difficult to completely prevent the dust from leaking.
In addition, when the blast gun is moved while some abrasive is clogged between the pipe and the rubber curtains provided as the anti-dust measures, a part of the pipe in sliding contact with the rubber curtains is abraded by a cutting force of the abrasive, and as a result, the pipe may be worn out in a shorter period of time in some cases.
Furthermore, according to the moving mechanism for a blast gun having the above structure, the movable region of the blast gun is restricted by the size, shape, and so on of the slit, and in addition, the moving direction of the blast gun is restricted in the longitudinal direction of the slit; hence, complicated movement or arbitrary movement cannot be achieved.
On the other hand, according to the blasting machine in which the moving mechanism for a blast gun, such as the robot, is accommodated in the blasting chamber, the slit through which the pipe is inserted into the cabinet is not necessarily provided, and measures for preventing the dust from leaking outside the cabinet are also not required. Furthermore, the movement is not restricted by the shape or the like of the slit, unlike the case in which a driving mechanism or the like is provided outside the blasting chamber, and it is thus possible to make the blast gun perform a relatively complicated movement.
However, as for the above moving mechanism, such as the robot, disposed in the blasting chamber, when it is accommodated therein without taking any measures, the moving mechanism is directly exposed to the dust in the blasting chamber, and hence failure or the like is liable to occur. Accordingly, it is necessary to take anti-dust measures for the robot or the like.
As the anti-dust measures described above, although the above-described robot or the like accommodated in the blasting chamber is covered by an anti-dust jacket in some cases, depending on the type of abrasive to be used and the process conditions, the jacket may suffer from the problem of being rapidly worn out. In addition, when the anti-dust measures are insufficient, the abrasive or the like may enter the jacket, thereby causing failure. In particular, for example, when the abrasive enters spaces formed between sliding portions, such as a bearing, a shaft, and a motor, a problem may arise in that these parts may become severely worn.
In addition, in blasting, the movement of a blast gun can be performed by a relatively simple motion in many cases, and hence the primary axial movement of the robot may not be required in many cases. Accordingly, when the robot is accommodated in the blasting chamber as described above, the blasting machine may be provided with performance higher than necessary one, and as a result, the cost of the blasting machine is unnecessarily increased.
Accordingly, the present invention has been conceived in order to solve the problems of the above conventional techniques, and an object of the present invention is to provide a moving mechanism for a blast gun for a blasting machine in which, although the structure is relatively simple, the blast gun accommodated in a blasting chamber can be easily moved, and other operations can also be easily performed; anti-dust measures are not required or can be easily provided; and although the structure is relatively simple, it is possible to make the blast gun perform a complicated movement. More particularly, an object of the present invention is to make the blast gun perform a complicated movement by the following means; that is, by operating input means of the present invention, an output arm 30 disposed in a blasting chamber 3 is pivotally moved, that is, arm members (first output arm 31 and second output arm 32) are rotated relative to each other so that the positions of the arms 31 and 32 can be changed.